Fluid handling systems often employ multiple valves that cooperate to perform related functions. For example, in a hydraulic system having a source of fluid pressure, multiple electronically controlled valves are often used to selectively load and unload the source or direct pressurized fluid from the source to one or more actuators. Each of the electronically controlled valves requires an associated driver and driver circuitry to control the function of the valve elements. This large number of drivers and driver circuitry can be expensive, complex, and increase the unreliability of the fluid handling system. In addition, when retrofitting an existing system with updated components, the existing system may not have the appropriate number of drivers and driver circuitry required to adequately support the additional components.
One way to simplify such a hydraulic system is described in U.S. Patent Application Publication No. 2004/0208754 (the '754 publication) published on Oct. 21, 2004 to McFadden et al. The '754 publication describes an electromechanical control system comprising a single input, dual adjustable output driver that can provide two separate control signals to load or unload two associated hydraulic implement pumps. In other words, the electromechanical control system can determine the speed of the pumps and, through separate control of the operation of two valves, open or close oil flow to a reservoir, thereby providing pressure and flow to the hydraulic system or recirculating oil back to an inlet of the two pumps.
Although the electromechanical control system of the '754 patent may simplify the associated hydraulic implement system, it may still be complex and expensive. In particular, although a single driver may be used to control operation of two separate valves, separate driver circuitry for each of the valves is still required. In addition, the driver is still required to output separate control signals to control each valve individually. This additional circuitry and complexity may increase the cost of the electromechanical control system.
The fluid control system of the present disclosure solves one or more of the problems set forth above.